dollar/thrifty, and health insurance provider wellpoint is trying to merge with amerigroup, a medicaid provider. but recently, the department of justice has shown its teeth when it comes to consolidation. last year, it blocked major deals between at&t and t-mobile, h&r block and tax act, and nasdaq and n.y.s.e. euronext. it did allow comcast and nbc to combine, but with strict conditions attached. >> i think most mergers get approved, regardless of the administration. i think, at the margin, there's been a little bit less predictability with this administration >> reporter: attorney j. mark gidley says this administration's guidelines for mergers, introduced back in 2010, give regulators more room for interpretation. they also leave businesses with a lot to consider before a merger. >> i think, in the past, it was a lot easier for a lawyer to say "yeah, you should be fine. there's ten competitors. it will go through." i think it's harder to predict now, and a board of directors, or two board of directors have to take a little bit more of a jump-off-the-cliff attitude with a merger.